Welcome to the board!! I have just turned 38 (days ago) and will be having my right knee replaced on Monday, March 18, 2013. I too have been told, over and over again, how very young I am and how it's best if I can wait until I'm 60.
After more than 20 years of knee issues, 6 surgeries and a very rapid decline this past year, I finally took matters in my own hands and started seeking second opinions.
In fact, I contacted to my previous OS who is now the acting Secretary of Health for our state and asked for his advice. I explained all the treatments I've tried in the last year and that I am still being told I am too young. He responded by giving me a name of the Director of Joint Replacement at Arlington Hospital and from that very first appointment I knew I was in the right hands.
My current OS explained that there is no cure for osteoarthritis but there are successful treatment options (TKR or PKR). He stated that generally, this is a disease of age and the majority of patients are 60 or older. This means that this treatment, is very effective for that age range. He said that younger patients can be challenging for some doctors because their joint may require this treatment, but it may then lead to revisions in the future.
Ultimately, my new doctor and I looked over the treatment options I've tried in the last year, as well as that daily function assessment that I brought with me and decided that it was time. In fact, when I told him of my goals post surgery (raising kids, family vacations, being a horse owner, exercise for fitness, teaching elementary school) he said that I could have those and more once I am recovered!!
Anyway, I certainly didn't mean to tell my story in your thread, but wanted you to know that you are NOT alone in this. Keep trying and certainly start seeking other doctors.
Good luck and keep us posted!